Catecholamine inotropes are routinely employed in the critical care setting to support heart function through their ability to increase cardiac contractility (see Chap. 3 for the structures of the catecholamine inotropes). For example, the inotropic agent, dobutamine is used in the treatment of congestive heart failure, epinephrine for the treatment of anaphylactic shock and dopamine to support renal function. Clinical evidence of the role of catecholamines, both endogenous and administered in...

The anatomical region where the tooth meets the gum (or gingiva) is particularly interesting as it is a junction between hard and soft tissue (Figs. 7.1a, b), where a nonshedding tooth surface may be colonised with dental plaque in close proximity to the supporting periodontal tissues. Within dental plaque, the pathogenic organisms and the various virulence factors they release, stimulate a reaction by the hosts' inflammatory and immune systems, indeed, a delicate equilibrium exists School of...

Stress is an intrinsic part of life, and successfully adapting to stimuli that induce stress is necessary for the survival of an organism in its environment that is constantly changing. Although there is not a commonly used definition of stress, the concept of stress is often broken down into the challenge (called the stressor) and the behavioral and physiological responses to this challenge (called the stress response). A stressor is any stimulus that disrupts internal homeostasis, and can...

Integral to the design of the original microbial endocrinology experiments was a commitment to use a bacterial inoculum that accurately reflected the infectious dose encountered in vivo. Therefore, the starting inocula used were low, typically these were around 10'-102 CFU ml, which was intended to reflect the numbers of pathogenic bacteria likely to be present at the start of an infection (Lyte and Ernst 1992, 1993 Freestone et al. 1999, 2002, 2003, 2007a, b, c). This use of low bacterial...

It has generally been observed that propagation of bacteria in traditional rich microbiological media, which typically allow good growth, frequently does not promote the strong expression of virulence determinants. Indeed, many bacteria will only express their adhesins, invasins or toxins when grown under the same temperature, pH, nutritional or atmospheric conditions that they would face on entry into the host. Consequently, when undertaking microbial endocrinology experiments, where the...

Historical chronologies of the neurotransmitters' discoveries are represented in Table 2.1. The first neurotransmitters were the catecholamines found by the American scientist John Jacob Abel at the end of the nineteenth century in extracts from animal adrenal glands. During the years 1906-1914, the existence of neurotransmitter compounds were identified not only in animals, but also in fungal extracts which were used as medicinal preparations. The twentieth century was the epoch for the...

In serum- or blood-supplemented media, the magnitude of bacterial growth stimulation possible with catecholamine stress hormones can be in 20 h or less up to a 5 logs higher than un-supplemented control cultures (reviewed in Freestone et al. 2008a). Figure 3.1 shows the wide variety of bacterial species that have been reported to be catecholamine-responsive. Although the spectrum of bacteria Fig. 3.1 The spectrum of stress-hormone responsive bacteria. Over 50 different types of bacteria...

Both NE and DA have been shown to alter the mucosal attachment or invasiveness of bacterial pathogens such as EHEC or serovars of Salmonella enterica not always through direct contact with these bacteria, but rather by acting on cells of the intestinal mucosa (Table 5.1). The actions of these catecholamines on bacteria-mucosa interactions have been examined in mucosal explants mounted in Ussing chambers (Brown and O'Grady 2008). This apparatus has been used for decades in studies of...

A critical point in the development of microbial endocrinology turned out to be a fortuitous meeting at the 1995 First International Rushmore Conference on Mechanisms in the Pathogenesis of Enteric Diseases, held in Rapid City, South Dakota. Following my presentation, I was approached by a bearded and pony-tailed Richard Haigh, at the time a Ph.D. student at Leicester University in the United Kingdom (and the same Dr. Haigh who is the author of Chap. 16). Richard's interest in my work served as...

The involvement of PNI in the creation of microbial endocrinology went far beyond the theoretical aspects described above. By 1992 I had obtained my first NIH grant which embodied a PNI approach examining the mechanisms by which stress could affect susceptibility to infectious disease. Although stress had been well recognized to affect susceptibility to infections for nearly 100 years (Peterson et al. 1991), I sought to identify relevant immune-based mechanisms through the use of the...

In order to verify that acute Pi depletion alone was sufficient to shift the lethality of P. aeruginosa in vivo, we modeled Pi depletion in the P. aeruginosa-C. elegans system (Fig. 9.2) (Zaborin et al. 2009). C. elegans normally feed on lawns of E. coli OP50 that grow on nematode growth media (NGM), a high Pi media (25 mM). We used P. aeruginosa PAO1, known to be non-lethal to C. elegans on NGM media, and depleted the media of Pi to determine if low Pi would shift P. aeruginosa to express...

Iron delivery from Tf and Lf is not the only mechanism by which catecholamines can enhance bacterial growth, at least for Gram-negative bacteria. Catecholamine-induced growth of enteric bacteria in a serum-based medium leads to the production of a non-LuxS dependent autoinducer (NE-AI) of growth (Lyte et al. 1996 Freestone et al. 1999). This novel AI is heat stable, very highly cross-species acting, and induces increases in the growth of a magnitude similar to that achievable with the...

E. coli is one of the most well-studied bacterium in the microbiology field due to its frequent incidence in different environments and hosts, as well as its use as a tool in molecular biology. Currently, there are several categories of E. coli known to cause disease, mainly diarrhea in humans, also named as diarrheiogenic E. coli. Among those, enterohemorrhagic E. coli O157 H7 (EHEC) is one of the most important pathogenic E. coli. EHEC has been associated with several recent food-borne...

The function of compounds named neurotransmitters originates from simple chemot-axis and chemosignaling of microbial cells and leads to intercellular communication (Fig. 2.1). The so-called neurotransmitters may regulate (as hormones) growth and development of other unicellular organisms, and be attractants or repellents for them. In higher concentrations the same substances also play a defense role (for saving or Fig. 2.1 The scheme of the evolution in the neurotransmitter (biomediator)...

The QseBC system was initially described as a two-component system regulated by quorum sensing, which shares homology with Salmonella enterica serovar Typhimurium PmrAB (Sperandio et al. 2002b). The same study showed that QseBC was involved in regulation of flagella and motility in EHEC. In a detailed study (Clarke and Sperandio 2005a), it was shown that QseBC constituted a two-component system, and that the qseBC genes were cotranscribed forming an operon. Moreover, it was reported that QseB...

As indicated earlier, increased faecal excretion of E. coli has been noted in pigs subject to social stress (Jones et al. 2001) or physical handling (Dowd et al. 2007). Evidence that such events may be correlated with the release of stress-related catecholamines is afforded by the observation that the selective neurotoxin 6-hydroxy-dopamine rapidly and dramatically increases the number of E. coli in the cecum of mice (Lyte and Bailey 1997). 6-hydroxydopamine destroys noradrenergic nerve...

The number and types of bacteria that reside as part of the indigenous microflora are thought to be relatively stable, but environmental and physiological challenges have been shown to disrupt this stability. For example, early studies by Schaedler and Dubos (1962) demonstrated that rehousing mice into new cages significantly decreased lactobacilli levels (Schaedler and Dubos 1962). And, chronic sleep deprivation in rats was shown to induce a significant overgrowth of microflora in the ileum...

It is clear that catechols ingested in the diet, or their derivatives, may be found in plasma and tissues at submicromolar and micromolar levels. These are comparable with, or higher than, normal plasma concentrations of norepinephrine and epinephrine, which are in the nanomolar range (Benedict and Grahame-Smith 1978) and, against this background, we shall shortly examine the evidence from two studies (Coulanges et al. 1998 Freestone et al. 2007c) that have shown that dietary catechols can...

As is evident from the information presented in this chapter, the field of fungal endocrinology encompasses a number of different areas and shows that these simple eukaryotic organisms can indeed have true hormone receptor interactions. Additional studies are needed in the search for endogenous hormones that regulate mating of higher fungi, such as the dermatophytes, or Coccidioides. The influence and interactions of mammalian hormones on pathogenic fungi remains an area for study that has thus...

14.3.5.1 Acyl Homoserine Lactones (AHLs) AHLs are lipophilic compounds secreted by a variety of species of Gram-negative bacteria that participate in intercellular communication by acting as ligands for inducible transcriptional regulatory proteins (Fuqua and Greenberg 2002). AHLs consist of a homoserine lactone ring joined to an acyl side chain that can vary in length, saturation, and side chain modifications. AHLs are synthesized by enzymes of the LuxI family utilizing S-adenosyl methionine...

Intravenous catheter-related bloodstream infections are invariably associated with increases in length of time in intensive care units and of course hospital costs (Crnich and Maki 2001). In an effort to combat bacterial colonization of catheter lines and any possible subsequent progression to catheter-related bloodstream infections, the use of antimicrobial impregnated catheters, particularly those incorporating antibiotics such as rifampin and minocycline, is becoming increasingly adopted in...

Secondary metabolites are compounds produced by an organism that are not required for primary metabolic processes, and in general, their absence does not result in immediate death of the organism. However, these metabolites may have significant effects on other organisms, for example, by acting as toxins. Secondary metabolites are produced by a wide range of microorganisms, including many species of bacteria and fungi, and include several that may be considered as candidate participants in...

Indigenous microflora are not invasive bacteria, which is one property that allows them to reside with their host. Moreover, the external surfaces of the body, i.e., cutaneous and mucosal surfaces, maintain a barrier to external substances, including microbes. In mucosal tissues, transport of solutes into the body is controlled in part through tight junctions between intestinal epithelial cells that prevent the passive transfer of molecules and microbes. Bacteria from mucosal surfaces, however,...

Though evidence exists that catecholamines partly exert their effects by acting on host tissues above , it is clear that during culture in vitro they promote the growth of Gram-negative bacteria of several genera and expression of their virulence factors. E. coli O157 H7, Salmonella enterica and Yersinia enterocolitica vary markedly in their ability to grow in response to catecholamines Freestone et al. 2007b . The response of Y. enterocolitica was limited to NE and DA, and these proved to be...